This invention relates generally to the printing industry and more particularly to stacking of cut imaged sheets of photographic media in imagesetters and platesetters.
The following terms are defined for clarity throughout this disclosure and the appended claims. An "imagesetter" is defined as a high resolution output device that takes rasterized, bitmapped data, such as a digital text or image file, generated by a raster image processor and writes it to a medium such as film or paper, commonly using a laser that exposes the medium line by line. A "platesetter" is an imagesetter which transfers the image directly onto a printing plate. Hereinafter, the term "imagesetter" will be used to denote either an imagesetter or platesetter as defined above. A "medium" as defined herein is a substrate to which an image is transferred in a printing process, whether chemically, thermally, photographically or mechanically. Media can be made of a variety of substances such as, but not limited to, paper, film, polyester, rubber, plastic, aluminum and other various metals and combinations.
Two conventional imagesetting systems, which will be referred to in the following discussion, are illustrated in FIGS. 1, 2 and 3. A conventional imagesetting system includes a workstation, an imagesetter and a processor. The system is designed to: (1) acquire an image in digital format using any known image acquisition device such as a scanner or digital camera; (2) allow alterations to the acquired image through the use of a computer workstation and, typically, off-the-shelf software image editing packages; (3) transform the altered digital image into bitmapped data via a raster image processor (RIP); (4) transfer the bitmapped data by exposure onto a medium or substrate; and (5) chemically process the exposed medium to yield a finished product. The finished product is a developed film or printing plate.
Alterations of the acquired image, as well as control of the various components of the imagesetting system 100, are provided by operator use of a workstation 50 as shown in FIG. 1. Although not explicitly shown, the workstation 50 or its equivalent could be used with the imagesetting systems of FIGS. 2 and 3. The workstation or computer system 50 includes a central processing unit (CPU) 40 and a variety of peripheral devices such as a monitor 42, a keyboard 44, a mouse 112, a CDROM port 46 and floppy disk ports 48, 49. The monitor 42, keyboard 44, mouse 112 and floppy disk port 49 are each electronically connected to the CPU 40 via a bus 52 which, in turn, communicates to the imagesetter 102 and the processor 104 via lines 54 and 56, respectively. CDROM port 46 and floppy disk port 48 are also connected to the other system components via lines 52, 54 and 56. Of course, other combinations of peripherals and computer equipment could be used, if desired, to provide similar control functions of the computer system 50.
After the image is acquired and edited as desired, the altered digital image is transformed into bitmapped data in the raster image processor. In this example, the CPU 40 performs the raster image processing. Alternatively, a separate raster image processor could be used in conjunction with the workstation 50.
The bitmapped or rasterized data is then transferred to a medium which is exposed in an internal drum imagesetter 102 using a light source such as a laser.
The exposed medium is then chemically processed in the wet chemical processor 104, which develops, fixes and washes the medium. After chemical processing, the imaged medium is dried, output and stacked into the output basket 106 of the system 100 of FIG. 1, or onto the stacking surface 230 of the system 250 of FIGS. 2 and 3. An enclosed dryer section (not shown) is built into, or attached to, the processor 104 of FIG. 1 whereby air is circulated and blown across the chemically processed medium for drying. Similarly, the imagesetting system 250 of FIG. 2 includes an enclosed dryer section 212 in which preferably warm air is circulated to assist in drying the imaged media prior to stacking. The enclosed dryer section 212 can be considered either as a part of the processor 104, or as a separate system component.
In the imagesetting system 100 of FIG. 1, the processed sheets of medial 05, 107 and 108 are extracted from the processor 104 and collected or stacked into the basket 106. The imagesetting system 250 of FIG. 2 eliminates the need for a basket 106 by use of a redirecting section 224 which redirects the media to be extracted from the processor 104 for stacking onto the upper surface 230 of the system 250. The stacking surface 230 could be defined by either the imagesetter 102 alone, the processor 104 alone, or the combined imagesetter and processor 250 and optionally with a side wall 118 adjacent to the ends of 116 of stacked media 107. Removal of the basket 106 from the imagesetting system 100 shrinks the footprint, i.e. the space, needed for the system.
A typical imagesetting system includes three main components: (1) a raster image processor which translates file information of an acquired and edited image into a bitmap, at the resolution of the image recorder; (2) an image recorder which uses laser imaging to expose the bitmap image on the medium; and (3) a processor which develops the medium to create the finished product. The imagesetter outputs color separations including high resolution halftones and other graphics, as well as type. Film imaged on the imagesetter is used to prepare a set of black-and-white or color proofs using a commercially available proofer. It is the designer's responsibility to carefully check the quality and completeness of the proofs which indicate the results expected on the printing press.
One internal drum imagesetter similar to the imagesetter 102 is described in U.S. Pat. No. 5,769,301 issued Jun. 23, 1998 to Herbert et al. Another internal drum imagesetting system is described in U.S. Pat. No. 5,699,099 issued Dec. 16, 1997 to Garand et al. Both of the above patents are herein incorporated by reference in their entirety for non-essential background information which is helpful in appreciating the applications of the present invention.
Typically within the imagesetter 102, a media supply cassette supplies a roll of image-receiving media such as photographic film. Alternatively, photo-sensitive printing plates or strips of film could be supplied. A predetermined length of the media is placed onto an internal drum where a rasterized image is transferred onto the medium via a laser light source. The imaged medium is thereafter removed from the inner surface of the drum and transported to the image processor 104 for chemically developing, fixing, washing and perhaps drying the medium.
FIG. 3 is a side view of the imagesetting system 250 of FIG. 2, schematically illustrating the workflow of the wet image processor 104. Specifically, the imaged medium 200 passes into the processor 104 via transport rollers 204. This particular processor contains: a developer section 206; a fixer section 208; a dual wash section 210; and a dryer section 212 enclosed in a housing 224. Each section performs a basic function to change the exposed medium into a fully developed and dry medium, ready for handling. The imaged film is transported through the processor entrance slot 202 where the transport roller system controls the movement of the film at an uniform speed through each of the four sections. The transport roller system includes: numerous roller pairs 216 in the developer section 206; numerous roller pairs 218 in the fixer section 208; numerous roller pairs 220, 222, and 211 in the wash section 210; and numerous roller pairs 214 in the enclosed dryer section 212.
In the developer section 206 the latent image created during exposure is developed, and in the fixer section 208 the developing process is stopped and unexposed silver halide is dissolved.
In the wash sections 210 any residual chemicals are washed off the medium. Fresh water is added from an external water supply. Any excessive water overflow is drained through overflow/drain tubes.
In the imagesetting system 100 of FIG. 1, the cut, imaged, processed and dried medium 108 is extracted from the processor 104 and is fed via rollers 110 into a storage basket 106. In the imagesetting system 250 of FIGS. 2 and 3, the medium 108 is extracted from the enclosed dryer section 212 of the processor 104 through a slot 226 and is thereafter stacked on the flat, planar surface 230 of the imagesetter 102 and the processor 104.